Distal Radius Fracture

Question 1

Briefly recap the anatomy of the distal radius

Answer 1

In the distal region, the radial shaft expands to form a rectangular end. The lateral side projects distally as the styloid process. In the medial surface, there is a concavity, called the ulnar notch, which articulates with the head of ulna, forming the distal radioulnar joint.

The distal surface of the radius has two facets, for articulation with the scaphoid and lunate carpal bones. This makes up the wrist joint.

Question 2

How common are distal radius fractures?

Answer 2

Fractures of the distal radius represent a quarter of all fractures seen clinically.

Question 3

What is a distal radius fracture?

Answer 3

The fractures occur through the distal metaphysis of the radius, with or without articular surface involvement.

Question 4

What are the 3 types of distal radius fracture? And which is most common?

Answer 4

1. Colles’ fracture (accounts for 90%)
2. Smith’s fracture
3. Barton’s fracture

Question 5

Who is commonly affected by distal radius fractures?

Answer 5

Due to osteoporosis, the risk of these fractures increases with age (termed ‘fragility fractures’).

However, children between 5-15yrs are also prone to these fractures.

Question 6

What is the most common cause of distal radius fracture?

Answer 6

Distal radius fractures are most commonly caused by a fall on an outstretched hand (FOOSH).

Question 7

Briefly describe the pathophysiology of distal radius fractures

Answer 7

The distal radius takes 80% of the axial load underneath the scaphoid and lunate fossae. A FOOSH causes a forced supination or pronation of the carpus; this in turn increases the impaction load of the distal radius.

Question 8

Briefly describe Colles’ fracture

Answer 8

A Colles’ fracture describes an extra-articular fracture of the distal radius with dorsal angulation and dorsal displacement, within 2cm of the articular surface. This type of fracture typically occurs as a “fragility fracture” in osteoporotic bone.

It occurs when a person falls forwards and plants their outstretched hand in front of them. The transfer of load as their body falls forces the wrist into supination.

Question 9

Briefly describe Smith’s fracture

Answer 9

This describes the volar angulation of the distal fragment of an extra-articular fracture of the distal radius (the reverse of a Colles fracture), with or without volar displacement.

This type of fracture is caused by falling backwards and planting the outstretched hand behind the body, causing a forced pronation type injury. These are less common.

Question 10

Briefly describe Barton’s fracture

Answer 10

This is an intra-articular fracture of the distal radius with associated dislocation of the radio-carpal joint.

A Barton fracture can be described as volar (more common) or dorsal (less common), depending on whether the volar or dorsal rim of the radius is involved.

Question 11

What are the risk factors for distal radius fractures?

Answer 11

The main risk factors for distal radius fractures are related to osteoporosis:

• Increasing age
• Female gender
• Early menopause
• Smoking or alcohol excess
• Prolonged steroid use

Question 12

What are the clinical features of a distal radius fracture?

Answer 12

Patients with a distal radius fracture typically present following an episode of trauma, complaining of immediate pain +/- deformity and sudden swelling around the fracture site. Any neurological involvement can also result in paresthesia or weakness.

Question 13

Briefly describe the examinations needed for a distal radius fracture

Answer 13

On examination, it is important to assess for any evidence of neurovascular compromise; check nerve function (see below) and limb perfusion (capillary refill time and pulses). Additionally, remember to examine the joints above and below to identify occult injuries.

Question 14

Which nerves need to be assessed in a distal radial fracture?

Answer 14

Median, ulnar and radial nerve.

Question 15

What are the motor and sensory functions of the median nerve?

Answer 15

Motor: abduction of the thumb.

Sensory: radial surface of distal 2nd digit.

Question 16

What are the motor and sensory functions of the ulnar nerve?

Answer 16

Motor: adduction of the thumb (‘Froment’s Sign’).

Sensory: ulnar surface of the distal 5th digit.

Question 17

What are the motor and sensory functions of the radial nerve?

Answer 17

Motor: extension of IPJ of thumb.

Sensory: dorsal surface of 1st webspace.

Question 18

What investigations should be ordered for distal radius fracture?

Answer 18

Plain radiographs are the quickest and definitive investigations of most fractures.

Further CT or MRI imaging may be used in more complex distal radius fractures, particularly for operative planning, however this can be performed once initial management steps have been made.

Question 19

What measurements aid with the diagnosis of a distal radius fracture?

Answer 19

Three measurements on a plain radiograph help with the diagnosis of a distal radius fracture:

• Radial height <11mm
• Radial inclination <22 degrees
• Radial (volar) tilt >11 degrees

Question 20

Briefly describe what can be seen on the X-ray

Answer 20

A Colles’ fracture is characterised by dorsal angulation and displacement.

Question 21

Briefly describe the conservative management of distal radius fractures

Answer 21

As for any trauma case), suitable resuscitate and stabilisation of the patient is the priority.

Once stabilised, all displaced fractures require closed reduction in the emergency department. Various techniques can be employed, however all involve ensuring sufficient traction and manipulation under anaesthetic. This can be performed under conscious sedation with a haematoma block or Bier’s block.

Following reduction, the arm should be restricted to allow for bone healing. Stable and successfully reduced fractures can typically be placed in a below-elbow backslab cast, then radiographs repeated after 1 week to check for displacement.

Once sufficient bone healing has occurred, patients should be rehabilitated via physiotherapy to ensure the regaining of full function.

Question 22

Briefly describe the surgical management of distal radius fractures

Answer 22

Significantly displaced or unstable fractures can require surgical intervention, as they have a risk of displacing further over time if not stabilised. Any fracture with an intra-articular step of the radiocarpal joint >2mm is also advised to be surgically corrected.

Options of surgical management include open reduction and internal fixation (ORIF) with plating, or K-wire fixation. External fixation is rarely used. Patients will be then placed in a cast to ensure ongoing immobility for a few weeks.

Question 23

What are the complications of distal radius fracture?

Answer 23

The main complications following distal radius fractures are:

• Malunion
• Median nerve compression
• Osteoarthritis

Question 24

How does malunion present following a distal radius fracture?

Answer 24

Poor realignment leads to a shortened radius compared to the ulnar, leading to reduced wrist motion, wrist pain, and reduced forearm rotation; can be treated with corrective osteotomy of the malunion.

Question 25

What are the differentials of distal radius fractures?

Answer 25

1. Forearm fracture (such as Galeazzi or Monteggia fractures)
2. Carpal bone fractures
3. Tendonitis or tenosynovitis
4. Wrist dislocation

Question 26

What is a monteggia and galeazzi fracture?

Answer 26

Monteggia – usually caused by a force from behind the ulna. The proximal shaft of ulna is fractured, and the head of the radius dislocates anteriorly at the elbow.
Galeazzi – a fracture to the distal radius, with the ulna head dislocating at the distal radio-ulnar joint.

Question 27

What name is given to the deformity in a Colles’ fracture?

Answer 27

It produces what is known as the ‘dinner fork deformity’.